1. Technical Field
The present invention relates to a sensor unit, a motion analysis device using the sensor unit, and the like.
2. Related Art
In a motion sensor which detects a motion of an object, the accuracy of a motion to be detected may change depending on a mounting method on the object. JP-A-2009-125507 describes a technique in which an object for motion detection is a person who makes a golf swing, and a motion sensor is put directly on the ear to detect an accurate motion of a head of the person.
However, when an object is a person, the person may be unwilling to bring the motion sensor into direct contact with the skin. When an object is, for example, an expensive item or a precious item, there is a need for avoiding the direct attachment of the motion sensor to the object. Even when an object is an item which is used in an athletic competition, the mounting of the motion sensor during the competition is banned by regulations, and there is a need for facilitating attachment and detachment. In this case, the motion sensor may be mounted on the object through an attachment, and there is a demand for detecting an accurate motion through the attachment.
The attachment is not limited to a hard fixing instrument. For example, when an object is a person, the person puts the gloves to which the motion sensor is attached, and the motion of the person is detected. At this time, the attachment is the soft gloves. The material for the attachment may change depending on the object for motion detection, or may be selected from a plurality of materials.
Noise which occurs due to the movement of the object is transferred to the motion sensor through the attachment. For example, a motion sensor is mounted on a skate blade through an attachment to detect a motion of an athlete. At this time, high-frequency noise which occurs due to minute unevenness of an ice surface is transferred to the motion sensor.
However, noise may be most absorbed or may not be absorbed by the attachment depending on hardness of the attachment. Accordingly, even when a sensor unit which includes a motion sensor and a filter passing a prescribed frequency band is used, if the type of the attachment changes, it is difficult to detect an accurate motion of an object to be measured.